1. Field of the Invention
The present invention relates generally to space ion thrusters.
2. Description of the Related Art
Ion thrusters have the capability to provide constant thrust with a high specific impulse for years. Thus ion thrusters have been utilized in spacecraft for long duration and inter-planetary missions. Current designs for ion thrusters use electron collision for propellant ionization.
Electron collision ionization sources bombard a gas atom with electrons that are emitted from a heated cathode. As the electrons collide with the gas atoms, they knock off one or more electrons. A relatively large chamber with magnets or RF fields to increase the electron path is required to maximize ionization. The newly created ions are drawn toward negatively-charged acceleration grids. Once the particles pass through these grids, they are sprayed with electrons from a conventional hollow-cathode source to neutralize the charged atoms.
The small amount of propellant mass required to operate ion thrusters for such a long time also makes ion thrusters attractive for use in small satellites and CubeSats; however, the size and mass of the electron bombardment chamber required for ionization to occur is too large for use in small satellites and CubeSats.